A Web-based experiment or "Internet-based experiment" is an experiment that is conducted over the Internet. Psychology and Linguistics are probably the disciplines that have used these experiments most widely, although a range of other disciplines use web-based experiments. Within Psychology most web-based experiments are conducted in the areas of Cognitive and Social Psychology. This form of experimental setup has become increasingly popular because researchers can cheaply collect large amounts of data from a wide range of locations and people. A web-based experiment is a type of online research method.
Web experiments have been used to validate results from laboratory research and field research and to conduct new experiments that are only feasible if done online. Further, the materials created for web experiments can be used in a traditional laboratory setting if later desired.
Interdisciplinary research using web experiments is rising. For example, a number of psychology and law researchers have used the web to collect data. Lora Levett and Margaret Bull Kovera examined whether opposing expert witnesses are effective in educating jurors about unreliable expert evidence. Rather than sensitizing jurors to flaws in the other expert's testimony, the researchers found that jurors became more skeptical of all expert testimony. In her experiment, this led to more guilty verdicts.
Levett and Kovera's research used a written transcript (law) of a trial, which participants then read before making their decision. This type of stimulus has been criticized by some researchers as lacking ecological validity—that is, it does not closely approximate a real-life trial. Many recommend the use of video where possible.
Researchers at New York University are currently conducting a psychology and law study that uses video of a criminal trial. Participants who go to the website can watch the trial (less than one hour long) and act as jurors.
Researchers at University of Salford are currently conducting a number of studies to explore sound perception. Sound experiments over the web are particularly difficult due to lack of control over sound reproduction equipment (see criticisms below).
A wide range of psychology experiments are conducted on the web. The Web Experiment List provides a way to recruit participants and archives past experiments (over 700 and growing). A good resource for designing a web experiment is the free Wextor tool, which "dynamically creates the customized Web pages needed for the experimental procedure" and is remarkably easy to use.
Laboratory experimentation has been a growing field in economics for the last decade or so. But the more experiments have been conducted in economics, the more the issue of an appropriate methodology and organization has been raised.
Some researchers have expressed concern that Web-based experiments have weaker experimental controls compared to laboratory-based ones. For instance, it may be difficult to be confident that the subjects characteristics are what they claim (e.g., age, race, gender, etc.) and that they are taking the experiment seriously. Others have argued (here and here) that brick-and-mortar experiments are just as affected by these problems, if not more so. Schoeffler et al. (2013) compared laboratory- and web-based results (62 and 1168 subjects) of an auditory experiment and found no significant differences.
- Reips, U.-D. (2007). The methodology of Internet-based experiments. In A. Joinson, K. McKenna, T. Postmes, & U.-D. Reips (Eds.), The Oxford Handbook of Internet Psychology (pp. 373-390). Oxford: Oxford University Press.
- Reips, U.-D. & Krantz, J. (in press). Conducting true experiments on the Web. In S. Gosling & J. Johnson, Advanced Internet Methods in the Behavioral Sciences. Washington, DC: American Psychological Association.
- Ulf-Dietrich Reips, Standards for Internet-Based Experimenting, 49 Experim. Psych. 243 (2002), available at http://www.psychologie.unizh.ch/sowi/reips/papers/exppsy/ExPsyReipsReprint.pdf.
- Levett & Kovera, The Effectiveness of Opposing Expert Witnesses for Educating Jurors about Unreliable Expert Evidence, 32 L. & Hum. Behav. 363 (2008), available at http://www.ncbi.nlm.nih.gov/pubmed/17940854.
- Virginia vs. McNamara, https://its.law.nyu.edu/webexp/namara001/
- Ben Greiner,An Online Recruitment System for Economic Experiments, http://ockenfels.uni-koeln.de/download/papers/orsee_billing.pdf
- Schoeffler et al. (2013). AN EXPERIMENT ABOUT ESTIMATING THE NUMBER OF INSTRUMENTS IN POLYPHONIC MUSIC: A COMPARISON BETWEEN INTERNET AND LABORATORY RESULTS, http://www.ppgia.pucpr.br/ismir2013/wp-content/uploads/2013/09/59_Paper.pdf